Hypermixer induced shock-vortex-plume interaction and mixing enhancement in a high Mach number supersonic flow

To achieve efficient fuel-air mixing in supersonic flows, this study employs large eddy simulation to investigate the streamwise vortices induced by alternating-wedge strut hypermixer and their interaction characteristics with shock waves and fuel plumes under Mach 3.5 flow conditions. A comprehensive analysis is conducted focusing on the influence of trailing-edge ramp angles (10°, 12.5°, 15°) and fuel injection angles (5°, 10°, 15°) on the evolution of streamwise vortices, plume expansion characteristics, and mixing performance. The results demonstrate that the hypermixer effectively induces a streamwise vortex with its circulation significantly enhanced by larger trailing-edge ramp angles. On average, circulation increases by approximately 14.3% when the ramp angle rises from 10° to 15° in the region upstream of fuel injection. Conversely, fuel injection reduces the vortex circulation, and this suppressive effect amplifies with increased injection angle. The lateral expansion and enhanced mixing are found to be primarily driven by vortex-induced entrainment and stretching. The plume converges toward the central vortex core, forming spiral-arm structures that expand the fuel-air interface and contribute to improved mixing efficiency. Within the shock-vortex interaction region, localized fluctuations in static pressure and Mach number are observed. However, integrated helicity and integrated enstrophy exhibit stable evolution throughout the interaction process. The theoretical breakdown criterion confirms that critical parameters remain consistently above the stability threshold, indicating the absence of streamwise vortex breakdown under non-reacting flow conditions. A marked improvement in mixing efficiency is observed with increasing trailing-edge ramp angles and injection angles, whereas the total pressure recovery exhibits only minor fluctuations across different configurations, stabilizing downstream at a high value close to 0.95. This investigation elucidates the tripartite coupling mechanism governing shock-wave/vortex/fuel-plume interactions at high Mach numbers, validating the configurational superiority of the hypermixer for mixing enhancement.